Natural: Volcanic Eruptions and Emissions
Emissions such as sulphates block out the sun and cause increases in cloud cover and rainfall.
Natural: Milankovich Cycles
The earth's orbit veries every 100,000 years.
The earth's axix changes every 42,000 yeras.
These could be an attributing factor to the change in climate.
A change in the earth's position in relation to the sun can affect the amount of solar energy which reaches the earth.
These cycles correlate well with past ice ages.
Natural: Plate tectonics
Land masses can drift to different latitudes.
Fold mountains can cause colder climates.
Natural: Changes in solar output/sun spots
Sun spots: a relatively dark and cool region on the Sun’s surface caused by the Sun’s magnetic field.
These sun spots work in cycles so the sun's energy changes over short periods of time.
Natural: Changes in ocean currents
Can affect the exchange of heat between the oceans and atmosphere.
Long term effects include the currents changing direction after ice ages.
Short term effects include El Nino/La Nina
Have caused major extinction events before - though to be the cause of the extinction of the dinosaurs.
Cause a reduction in radiation, a depeletion of the ozone layer and a lowering of global temperatures.
Deforestation is the clearance of forests by logging and/or burning
Causes a loss of carbon sinks.
Anthropogenic: Carbon Dioxide
Has a life of 100 years so stays in the atmopshere for a very long time.
Caused by the burning of fossil fuels.
Anthropogenic: Nitrous Oxide (N2O)
A greenhouse gas found in fertilisers.
200 to 300 times more effective in trapping heat than carbon dioxide.
Nitrous oxide has one of the longest atmosphere lifetimes of the greenhouse gases, lasting for up to 150 years.
CFCs were used as spray can propellents, solvents, cleaners and coolants until the mid 1970s. Many of the world's nations agreed to control the use of CFCs in 1987 when they signed the Montreal Protocol on Substances that depleted the ozone layer.
The warming effect that they produce ranges from 3000 to 13000 times that of carbon dioxide
They can remain in the atmosphere for up to 400 years.
Caused by coal mining, cattle flatulence, and rice production.
It produces 21 times as much warming as CO2.
Accounts for 20% of greenhouse gases.
Methane remains in the atmosphere for 11-12 years.